Physics - Waves

Question 1

how to waves transfer energy

Answer 1

causing particles of matter to oscillate

Question 2

longitudinal waves characteristic

Answer 2

oscillation are parallel to direction of energy transfer

Question 3

longitudinal waves examples

Answer 3

sound waves
p waves

Question 4

transverse waves characteristics

Answer 4

oscillations are perpendicular to direction of energy transfer

Question 5

transverse waves example

Answer 5

electromagnetic waves
(microwaves, light, UV)

Question 6

what is compression

Answer 6

compressed region

Question 7

what is rarefaction

Answer 7

stretched region

Question 8

wavelength

Answer 8

distance between a point on a wave and the closest next point which is exactly identical

represented by lambda

Question 9

amplitude

Answer 9

maximum distance a particle can be displaced from rest position

Question 10

frequency

Answer 10

number of waves passing a point per second, measured in Hertz (Hz)

1Hz is equivalent to 1 complete wavelength per second

Question 11

sound waves that have higher amplitude

Answer 11

louder

Question 12

sound waves that have higher frequency

Answer 12

higher pitch

Question 13

wave speed

Answer 13

distance travelled by wave over time

Question 14

speed equation

Answer 14

frequency (Hz) x wavelength

Question 15

relationship between frequency and wavelength

Answer 15

inversely proportional

Question 16

speed of longitudinal waves through different states of matter and why

Answer 16

solid - fastest
liquid - fast
gases - slowest

transfer energy by causing particles to oscillate

Question 17

sound waves cant travel in a …

Answer 17

vacuum

Question 18

why can EM waves travel through a vacuum

Answer 18

particles oscillating in an EM are the electrons of the wave itself, which means it does not require additional matter and is able to travel through a vacuum

Question 19

speed of waves when travelling through matter

Answer 19

• speed depends upon medium/density of medium
• frequency is usually constant
• changes in speed changes wavelength (speed and wavelength are directly proportional)

Question 20

radiowaves
wavelength
uses
dangers

Answer 20

wavelength = >10cm

uses = communication

dangers = none?

Question 21

microwaves
wavelength
uses
dangers

Answer 21

wavelength = 10^-2 m

uses = wavelengths that pass through water are used for communication, wavelengths absorbed by water are used for cooking

dangers = must be kept inside of microwave by metal grill or could heat body

Question 22

infrared
wavelength
uses
dangers

Answer 22

wavelength = 10^-5 m

uses = heat is radiated as infrared - uses for heat cameras, cooking e.g. grilling toasting etc

dangers = responsible for burns and greenhouse effect

Question 23

visible light
wavelength
uses
dangers

Answer 23

wavelength = 10^-7 m

uses = optical fibres

dangers = eye damage

Question 24

ultraviolet
wavelength
uses
dangers

Answer 24

wavelength = 10^-8 cm

uses = fluorescent marking (chemicals are used which absorb UV light and emit visible)

dangers = skin cancer, ionising radiation

Question 25

x ray wavelength uses dangers

Answer 25

wavelength = 10^-10 cm uses = medical imaging dangers = ionising radiation

Question 26

gamma wavelength uses dangers

Answer 26

wavelength = 10^-12 uses = sterilising, cancer, radiotherapy, medical imaging dangers = ionising radiation

Question 27

relationship between EM's energy and EM's frequency

Answer 27

directly proportional

Question 28

relationship between EM's energy and EM's wavelength

Answer 28

inversely proportional

Question 29

what speed do EM waves travel at

Answer 29

speed of light all at the same speed

Question 30

reflection

Answer 30

occurs when a wave bounces off a surface without being absorbed by it - usually causes the wave to change direction

Question 31

law of reflection

Answer 31

angle of incidence = angle of reflection

Question 32

refraction

Answer 32

occurs when a wave enters a medium with a different optic density and change direction due to a change in speed

Question 33

which line are both angle of incidence and angle of reflection measured relative to

Answer 33

normal

Question 34

what is the normal

Answer 34

imaginary line at 90 degrees to the surface

Question 35

what colour is the end of the spectrum which is refracted least when entering prism

Answer 35

red

Question 36

what colour is the end of the spectrum which is refracted most when entering prism

Answer 36

blue

Question 37

will sound waves reflect and refract

Answer 37

yes

Question 38

doppler effect

Answer 38

when there is relative motion between a source of waves and an observer, the wavelength and frequency of the waves received when there is no relative motion

Question 39

doppler effect when source moves toward observer

Answer 39

frequency increases wavelength decreases

Question 40

doppler effect when source moves away from observer

Answer 40

frequency decreases wavelength increases

Question 41

what causes greater doppler shift

Answer 41

faster movement

Question 42

how are sound waves produced

Answer 42

from a vibrating source causes medium to vibrate and pattern of vibrations travels away from source as sound waves

Question 43

sound wave : frequency

Answer 43

PITCH same as frequency as vibration from source

Question 44

sound wave: amplitude

Answer 44

LOUDNESS depends in the amplitude of vibrations of the source

Question 45

sound wave: speed

Answer 45

determined by medium through which they are travelling through and NOT by the source

Question 46

what happens when sound arrives at detector

Answer 46

sequence of compressions and rarefactions causes pressure at the detector to vary this exerts a varying force on the detector and this is what is detected (eardrum moved by this force)

Question 47

echo

Answer 47

sound heard after sound waves reflect from one or more surfaces

Question 48

reflection can be used to measure distances equation

Answer 48

distance = velocity x time x 1/2

Question 49

what principle is used by both sonar and ultrasound

Answer 49

distance = velocity x time x 1/2 principle that dividing by two accounts for the fact that time is measured is time taken for the wave to travel from the emitter/reciever to the object and back again

Question 50

human hearing range

Answer 50

20Hz --> 20KHz

Question 51

ultrasound range

Answer 51

> 20KHz

Question 52

ultrasound

Answer 52

- depth detection - non invasive medical procedures - ultrasound can detect a boundary between different tissue types as certain fractions of ultrasound are reflected at each boundary - create image of soft tissue within body

Question 53

ultrasound: what does the time taken for the reflected waves to reach detectors correspond to

Answer 53

depth of each boundary